Dust and splash-proof filter

ABSTRACT

Embodiments relate generally to a filter ( 110 ), for example, for attachment onto a gas detector device or a gas sensor, and attempt to improve the efficiency and service life of the filter ( 110 ). Embodiments typically comprise a dustproof membrane ( 114 ) and a waterproof membrane ( 113 ). Some embodiments may also comprise a splash-proof cap ( 130 ) and/or features to reduce negative pressure on the filter ( 110 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

FIELD

Embodiments generally relate to filtration of air intake, for example,with regards to gas detector or gas sensor devices.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, referenceis now made to the following brief description, taken in connection withthe accompanying drawings and detailed description, wherein likereference numerals represent like parts.

FIG. 1 illustrates a cross-sectional view of an exemplary embodiment ofa filter and a splash-proof cap;

FIG. 2 illustrates an exploded view of an exemplary filter of FIG. 1;

FIG. 3 illustrates a perspective view of a bottom housing of anexemplary filter comprising entry apertures and a raised lip around theperimeter;

FIG. 4 illustrates a perspective view (from the bottom exterior angle)of a splash-proof cap comprising entry apertures, baffles, and,optionally, raised lips around the perimeter of each aperture;

FIG. 5 illustrates a perspective view (from a top interior angle) of asplash-proof cap comprising baffles;

FIG. 6 illustrates an exploded view of an exemplary filter of FIG. 1;

FIG. 7A illustrates a perspective view of an exemplary embodiment of afilter and a splash-proof cap;

FIG. 7B illustrates a sectional view of an exemplary filter and anexemplary splash-proof cap, wherein the direction of airflow isindicated via arrows;

FIG. 8 illustrates a sectional view of an exemplary filter and anexemplary splash-proof cap, wherein the direction of water flow isindicated via arrows.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrativeimplementations of one or more embodiments are illustrated below, thedisclosed systems and methods may be implemented using any number oftechniques, whether currently known or not yet in existence. Thedisclosure should in no way be limited to the illustrativeimplementations, drawings, and techniques illustrated below, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

The following brief definition of terms shall apply throughout theapplication:

The term “comprising” means including but not limited to, and should beinterpreted in the manner it is typically used in the patent context;

The phrases “in one embodiment,” “according to one embodiment,” and thelike generally mean that the particular feature, structure, orcharacteristic following the phrase may be included in at least oneembodiment of the present invention, and may be included in more thanone embodiment of the present invention (importantly, such phrases donot necessarily refer to the same embodiment);

If the specification describes something as “exemplary” or an “example,”it should be understood that refers to a non-exclusive example;

The terms “about” or “approximately” or the like, when used with anumber, may mean that specific number, or alternatively, a range inproximity to the specific number, as understood by persons of skill inthe art field (for example, +/−10%); and

If the specification states a component or feature “may,” “can,”“could,” “should,” “would,” “preferably,” “possibly,” “typically,”“optionally,” “for example,” “often,” or “might” (or other suchlanguage) be included or have a characteristic, that particularcomponent or feature is not required to be included or to have thecharacteristic. Such component or feature may be optionally included insome embodiments, or it may be excluded.

The embodiments of the disclosure typically relate to a filterconfigured to attach to a gas detector or a gas sensor. Due to varyingambient conditions, gas detectors generally may not provide accuratemeasurements using unfiltered air. For example, in dusty or moistenvironments the filters may either clog or lose effectiveness and,typically, cannot be effectively used outdoors. In another example,entry of large drops of water (for example, due to splashing) maycompromise a filter. Furthermore, use of a single filter may negativelyimpact filter life, since dust and other particulates may interfere withsuch a filter's ability to block water without clogging. Additionally,if the amount of negative air pressure experienced by the filter is toohigh, water saturation/seepage may be a problem. Embodiments of thepresent invention may address one or more of such issues in an attemptto provide enhanced filtration of air for gas detectors/sensors or othersuch devices with air intake.

Disclosed embodiments relate to a filter (for example, for filteringinput air flow to remove dust, particulates, and/or moisture), whichmight, for example, be used for the air input of a gas sensor ordetector. Typically, disclosed filter embodiments would include twoseparate filtration membranes. For example, a dustproof membrane and awaterproof membrane positioned to operate in series (for example, withthe dustproof membrane being located upstream of the waterproof membrane(such that air would first flow through the dustproof membrane beforepassing through the waterproof membrane) (although other configurations(such as the waterproof membrane being upstream of the dustproofmembrane) may also be included within the scope of this disclosure)).Typically, the two filtration membranes would be located within ahousing (which typically encloses the two filtration membranes and,generally, includes an inlet and an outlet for directing air through thefiltration membranes and out to the air inlet (for example, for a gasdetector or gas sensor or other sensor requiring an air input).Additionally, for manufacturing purposes, the housing may be twoseparate elements which can be joined together around the two filtrationelements. Thus, disclosed filter embodiments would typically comprise: atop housing, having at least one outlet aperture; a bottom housing,having one or more inlet apertures; a dustproof membrane; and awaterproof membrane (and as noted above, the dustproof membrane oftenwould be located upstream of the waterproof membrane).

Typically, the two filtration membranes would be spaced apart (e.g. notcontacting one another), for example with the dustproof membrane beingspaced approximately 1, 2, 3, 1-3, 1-5, 2-3, 2-5, or 3-5 millimetersfrom the waterproof membrane. While persons of skill should appreciatethe types of materials which would function effectively as a dustproofmembrane and/or waterproof membrane, an exemplary dustproof membranemight comprise polypropylene nonwoven (PPNW) while an exemplarywater-proof membrane might comprises polytetrafluoroethylene (PTFE). Insome embodiments, each of the one or more inlet apertures would have anopen diameter of approximately 6-7 millimeters (and typically theremight be six such inlet apertures), while the outlet aperture would havean open surface area of approximately diameter of approximately 6millimeters or less. In other words, the ratio of the size of the inletapertures to the size of the outlet aperture might be approximately 6 to1 or larger. By having a larger inlet aperture area compared to theoutlet aperture area, the negative pressure on the filtration membranesmay be reduced, which, for example, may reduce the risk of waterseepage/saturation of the filtration membranes in a way that couldnegatively impact filter performance or life.

Some embodiments may have the waterproof membrane attached/affixed(typically in a permanent, sealing manner) to a top surface of thebottom housing. For example, such attachment may be by welding (forexample, sonic welding). Embodiments may also optionally have a supportframe located between the dustproof membrane and the waterproofmembrane. For example, the dustproof membrane may be located below andin contact with the support frame. In some embodiments, the waterproofmembrane may be spaced above the support frame. Typically, the supportframe will be configured to allow airflow therethrough, so that air mayflow through the dustproof membrane and then into the waterproofmembrane without significant obstruction and/or turbulence. So, forexample, in some embodiments the support frame might include one or moreair flow apertures, with the one or more air flow apertures typicallycorresponding with (for example, sized similarly and/or positioned inalignment with) the one or more inlet apertures in the bottom housing.

Embodiments of the disclosed filter may also include features which theApplicant has found may protect the filtration elements from splashesand other large water intrusion. For example, the bottom housing maycomprise a raised lip extending around the perimeter or circumference ofthe bottom surface of the bottom housing. Some embodiments may have (forexample, either in conjunction with or instead of the raised lip aroundthe perimeter of the bottom housing's bottom surface) a raised lip oredge or wall around the perimeter or circumference of each of the inletapertures in the bottom housing of the filtration device. One or moreembodiment may also include comprising a splash-proof cap, which mightbe a separate element which is either permanently affixed to the bottomhousing or (more typically) which is removably affixed to the bottomhousing of the filter. So, for example, the splash-proof cap wouldtypically comprise a hollow body with a top open end configured forattachment onto the bottom housing.

The splash-proof cap is generally designed to shield the filter fromsplashes or other liquid water intrusions and/or to direct any waterwhich does enter the filter (for example, either via splashes of liquidwater or condensation from moist air which might condense, for example,at the waterproof membrane) outward. So, for example, the bottom surfaceof the hollow body typically would have one or more entry apertures,which would typically be located on the bottom surface of the hollowbody (and, typically, the entry apertures might be sized similarly toand/or aligned with the inlet apertures on the bottom housing of thefiltration device), and typically the bottom surface of the hollow bodywould be curved inward (e.g. curved to form a bowl-like shape whichwould direct any water entering the hollow body towards the center ofthe bottom surface of the hollow body of the splash-proof cap) withrespect to the hollow body. Furthermore, the splash-proof cap typicallywould have one or more baffles, which would be configured with respectto the entry apertures of the splash-proof cap to block easy or directentry of water through the entry apertures (beyond the point of thebaffles) (while allowing airflow therethrough). While it could bepossible to have a single baffle which is configured to shield all ofthe entry apertures (and this embodiment is included within the scope ofthis disclosure), more typically there would be one baffle for eachentry aperture (e.g. direct or one-to-one correspondence). Regardless,the one or more baffles would typically correspond with the one or moreentry apertures in the bottom surface.

Typically, each of the baffles would be aligned with the correspondingentry aperture (for example, positioned over the entry aperture and/orsharing a common vertical centerline). And while the baffles could beshaped and/or oriented in various ways configured to effectivelyblock/shield water entry through the entry apertures, typicalembodiments might have each baffle oriented generally parallel to thecorresponding entry aperture and/or with each baffle sized to be atleast as large as the corresponding entry aperture (although in someembodiments, the baffles could be slightly smaller in size than theircorresponding entry aperture). The baffles are typically inset slightlyin the hollow body of the splash-proof cap, such that they mayeffectively block/shield from entry of water while allowing airflowaround the baffles via the inset. So, for example, each of the one ormore baffles would typically be located within the hollow body of thesplash-proof cap (e.g. within the hollow cavity of the splash-proof cap)and spaced approximately 3-4 millimeters from the corresponding entryaperture (e.g. inset approximately 3-4 millimeters from the bottomsurface of the hollow body of the splash-proof cap). Typically, theentry apertures of the splash-proof cap would have an open surface areaat least as great as that of the inlet apertures of the bottom housing.

In some embodiments, the bottom surface of the hollow body of thesplash-proof cap might optionally include a raised lip (or wallextension or edge) around the perimeter/circumference thereof. Also,some embodiments might include (either alone or in conjunction with theperimeter raised lip) a raised lip (or wall or edge) around theperimeter of each of the entry apertures (such that the bottom surfaceof the hollow body of the splash-proof cap is inset from the actualopenings of the entry apertures or such that the actual opening of theentry apertures projects or extends out (for example, downward) (forinstance, like a tube for each entry aperture) from the bottom surfaceof the hollow body of the splash-proof cap). In some embodiments, one ormore of the features of the splash-proof cap might instead be associatedwith the bottom housing of the filter (for example, the bottom surfaceof the bottom housing might be curved inward, there could be bafflescorresponding to the inlet apertures of the bottom housing of thefilter, and/or there could be a raised lip about the perimeter of thebottom housing and/or each of the inlet apertures similar to thosedescribed above with respect to the splash-proof cap).

Often, the splash-proof cap would be removably attached to the bottomhousing. For example, the splash-proof cap might further comprise anelastomeric bumper on an inner surface of the hollow body, configured toallow press-fit attachment of the splash-proof cap to the bottomhousing. Typically, the press-fit attachment would be sufficient toprevent entry of water and/or air (e.g. sealed) so that the onlyentryway to the filter (e.g. the inlet apertures of the bottom housing)would be through the entry apertures at the bottom of the splash-proofcap and/or would be sufficient to securely hold the splash-proof cap inplace on the bottom housing (so it would not fall off during routineusage). Alternatively, the splash-proof cap might be screwed on (withcorresponding screw threads on the bottom housing and the top of thesplash-proof cap) or otherwise removably attached. And in someembodiments, the splash-proof cap could be permanently attached (forexample via adhesive or welding) to the bottom housing. While persons ofskill should understand the disclosed embodiments based on the abovedisclosure, the following figures may provide specific examples that mayfurther clarify the disclosure.

Turning now to the drawings, FIG. 1 illustrates an exemplary embodimentof a filter 110 comprising a top housing 111, a bottom housing 112, atleast two filtering membranes, and, optionally, a splash-proof cap 130.The top housing 111 may comprise at least one outlet aperture 119(typically approximately 6 millimeters or less in diameter) configuredto attach snugly (for example, with flexible tubing), for example, to agas detector. While the outlet apertures 119 may be located anywhere onthe top housing 111 and be of any shape, in FIG. 1, the single outletaperture 119 is located on the center axis (at the top housing 111) andis tubular in shape. The bottom housing 112 may be located upstream ofthe top housing 111 and may comprise one or more inlet apertures (eachtypically having a diameter of 6-7 millimeters). The inlet apertures mayhave a large enough open surface area to allow for a sufficient volumeof air to flow through the filter 110, and, typically, the ratio of theopen surface area of the outlet aperture 119 to the inlet aperture wouldbe approximately, for example, 1 to 6 if there are 6 inlet apertures andone outlet aperture, as shown in FIG. 1 (which may reduce negativepressure effects on the membranes). Typically, the top and bottomhousing (111, 112) may be welded together via supersonic welding to forma water-proof seal, such that the housing (found at the top and bottom)encases the filtration membranes.

In the embodiments of FIG. 1, the filter 110 may comprise a waterproofmembrane 113, support frame 115, and dustproof membrane 114, all locatedwithin the housing. The waterproof membrane 113 may be locateddownstream (e.g. above) the dustproof membrane 114 in FIG. 1.Additionally, the support frame 115 may be located between thewaterproof membrane 113 and the dustproof membrane 114. Typically, thewaterproof membrane 113 of FIG. 1 is formed of polytetrafluorethylene(PTFE), and the dustproof membrane 114 of FIG. 1 is formed ofpolypropylene nonwoven (PPNW). The distance (e.g. gap) between thewaterproof membrane 113 and the dustproof membrane 114 may be 1-3, 2-3,1-5, 2-5, or 3-5 millimeters in FIG. 1, and the dustproof membrane 114may contact the support frame 115 (for example, with the support frame115 resting atop and contacting the dustproof membrane 114). The supportframe 115 may, in some embodiments, fit snuggly within the bottomhousing 112. The support frame 115 of FIG. 1 may comprise one or moreairflow apertures, with the airflow apertures of FIG. 1 aligning withthe inlet apertures in the bottom housing 112. In some embodiments, thesupport frame 115 may serve a spacing function between the waterproofmembrane 113 and the dustproof membrane 114 (although in FIG. 1, thereis a gap between the support frame 115 and the waterproof membrane 113)and/or may be the same diameter as the waterproof membrane 113 anddustproof membrane 114 to snugly fit within the housing.

In FIG. 1, the filter 110 may also comprise a removable splash-proof cap130 configured to prevent liquid water from communicating with thefilter 110. The splash-proof cap 130 may comprise a hollow body 131 witha top opening large enough to fit snugly onto the bottom housing 112. InFIG. 1, the hollow body 131 is tubular, but it may be of any shape orsize in other embodiments (so long as it can attach snugly to the bottomhousing 112). Additionally, the splash-proof cap 130 may comprise one ormore entry apertures 133 in its bottom end and one or more baffles 132.The entry apertures 133 may communicate with the outside ambientenvironment and may be operable to allow airflow into the open cavity ofthe hollow body 131 and into the filter 110. The entry apertures 133 ofFIG. 1 typically would have an open surface area at least as great asthat of the inlet apertures in the bottom housing 112. In FIG. 1, theentry apertures 133 are typically aligned with the inlet apertures andsized similarly. The baffles 132 may be spaced approximately 3-4millimeters inward (e.g. inset) from the entry apertures 133 and mayprevent water from entering into the hollow body 131. Also, in FIG. 1,the bottom surface 134 may be configured to curve inward with respect tothe hollow body 131 to serve a bowl-like function to direct the waterblocked by the baffles 132 to drain out of the entry apertures 133.

FIG. 2 illustrates an exploded view of an exemplary filter 210 of thetype shown in FIG. 1 where the filter comprises a top housing 211,water-proof membrane 213, support frame 215, dustproof membrane 214, andbottom housing 212. As discussed in reference to FIG. 1, there may beone or more outlet apertures 219 on the top housing 211 (which couldvary in shape and location), but the embodiment of FIG. 1 typically hasa single, centrally located outlet aperture 119. In addition, the hollowprojection 116 for the outlet aperture 219 may comprise ridges toprovide frictional force to snugly hold the gas detector tubing inplace. The waterproof membrane 213 of FIG. 2 may be formed of PTFE andmay be welded onto the housing via supersonic welding. Typically, thewaterproof membrane 213 may have a diameter large enough to fit snuglywithin the housing. Located upstream of the waterproof membrane 213,there may optionally be a support frame 215. The support frame 215 ofFIG. 2 comprises one or more airflow apertures 220 which may align withthe inlet apertures in the bottom housing 212 (and in FIG. 1, theairflow apertures are sized similarly to the inlet apertures). In someembodiments, the support frame 215 may be configured to serve a spacingfunction between the waterproof membrane 213 and the dustproof membrane214. In other embodiments, the support frame 215 may contact thewaterproof membrane 213 and dustproof membrane 214. Typically, thedistance between the waterproof membrane 213 and the dustproof membrane214 may be 1-3, 1-5, 2-3, 2-5, 1-10, or 5-10 millimeters. This distance(e.g. gap) may prolong the service life and efficiency of the filter210, and may provide sufficient space for any condensing water to exitthe housing before saturating through the waterproof membrane 213.Located upstream of the support frame 215, there may be a separatedustproof membrane 214 in FIG. 1. The dustproof membrane 214 may beformed of PPNW and may have a diameter large enough to fit snugly withinthe housing (but in any case, the dustproof membrane 214 should coverall inlet apertures). Further upstream of the dustproof membrane 214 inFIG. 2, there may be a bottom housing 212 (with the dustproof membrane214 typically contacting the bottom housing 212). The bottom housing 112of FIG. 1 comprises a recessed portion extending downward (e.g.upstream) from a rim or flange, and, typically, comprises one or moreinlet apertures. In FIG. 1, there are six inlet apertures, andtypically, each aperture has a diameter between 6-7 millimeters.Optionally, each of the one or more inlet apertures 317 shown in FIG. 3may have a raised lip extending around the perimeter. And as shown inFIG. 3, the bottom housing 312 may also comprise a raised lip 318extending downward (e.g. upstream) around a perimeter of the bottomsurface of the bottom housing 312.

FIGS. 4-5 illustrate a splash-proof cap embodiment 430 (similar to thatin FIG. 1) comprising one or more entry apertures 433 and one or morebaffles 532, wherein the baffles 532 may be configured to align with theentry apertures 433. In FIG. 4, the bottom of the splash-proof cap 430comprises seven entry apertures 433, which are typically sized similarlyto the inlet apertures (and, typically, in some embodiments, the baffles534 may be spaced approximately 3-4 millimeters away from the entryaperture 433 and may be located within the hollow body). Additionally,the baffles 532 may be positioned to be parallel to the correspondingentry aperture 433 and may have a surface area at least as large as thecorresponding aperture. In other embodiments, the entry apertures 433may comprise a raised lip 436 extending around the perimeter of eachaperture. Also, in some embodiments, the splash-proof cap 430 maycomprise a raised lip 435 extending around the perimeter of the bottomsurface.

Although in FIG. 4, the number of baffles 532 coincide directly with thenumber of entry apertures 432, it should be made clear that the numberof baffles 532 do not have to be the same as the number of entryapertures 433. For example, one baffle 532 with a larger surface areathan the surface area of the entry apertures 433 could be aligned withthe entry apertures 433 to prevent water from splashing in.

FIG. 5 better illustrates that the splash-proof cap 530 may have acurved bottom surface. The baffles 532 may be configured to preventwater from splashing in through the entry apertures 433 while alsoallowing air flow from the surrounding environment. The bottom surface534 may be configured to curve inward with respect to the hollow body toallow returned water to seep out of the embodiment (via the entryapertures) and back into the surrounding environment.

FIG. 6 illustrates an exploded view of the exemplary filter of FIG. 1,further illustrating that the splash-proof cap 630 may have anelastomeric bumper 637. The splash-proof cap 630 may be configured forattachment onto the bottom housing 612. In some embodiments, thesplash-proof cap 630 may be configured for removable attachment. Forexample, as shown in FIG. 6, the splash-proof cap 630 may press-fit ontothe bottom housing 612 via the elastomeric bumper 637 (with theelastomeric bumper 637 providing an interference fit that securely holdsthe splash-proof cap 630 onto the bottom housing 612 and seals theconnection). In other embodiments, the splash-proof cap 630 may screwonto the bottom housing 612. Generally, the splash-proof cap 630 may betubular comprising a hollow body with an open cavity as illustrated inFIG. 6. However, in some embodiments, the splash-proof cap 630 may be ofany size or shape as long as the splash-proof cap 630 comprises a hollowbody to allow air to communicate with the filter and is configured tosnugly fit onto the bottom housing 612. The splash-proof cap hollow bodytypically has a depth greater than 5 millimeters, for example 5-10millimeters or 5-15 millimeters.

FIG. 7A illustrates an exterior, perspective view of an exemplaryembodiment of a filter with a splash-proof cap. FIG. 7B illustrates asectional view of an exemplary filter 710 and an exemplary splash-proofcap 730 (similar to FIG. 1), wherein the direction of airflow from thesurrounding environment is indicated via arrows. Typically, airflow isinduced by the gas sensor attached to the outlet aperture 719, which forexample, may pump air through the filter 710 and into the gas pipe (forexample, using a fan). Thus, the air from the ambient environment may bedrawn in and flow through the entry apertures 733 in the splash-proofcap 730 and may communicate with the baffles 732 which are directlyaligned with the entry apertures 733. The air may then travel around thebaffles 732, travel through the hollow body 731, travel through theapertures in the bottom housing, permeate through the dustproof membrane714, travel through the airflow apertures in the support frame 715,permeate through the waterproof membrane 713, exit through the outletaperture 719, and, lastly, communicate with the gas detector device (forexample, via tubing connected to the outlet aperture).

During the process of airflow through an exemplary embodiment, water mayalso communicate with an exemplary filter 810 and an exemplarysplash-proof cap 830 as shown in FIG. 8. In some cases, humid/moist airmay travel through the entry apertures 833, communicate with the baffles832, travel through the hollow body 831, travel through the inletapertures, permeate through the dustproof membrane 814, travel throughthe air flow apertures in the support frame 815, and condense at thewaterproof membrane 813. Once the moisture condenses to form water, thewater may trickle down into the hollow body 831 and contact the bottomsurface of the splash-proof cap 830. Once at the bottom surface (whichis configured to be curved inward with respect to the hollow body 831 orotherwise configured to direct water out of the entry apertures 833),the water may exit through the entry apertures 833. In other cases,splashing water from the ambient environment may contact thesplash-proof cap 830. In this case, the one or more baffles 832 mayprevent any splashes from communicating with the filter 810. The watermay enter through the entry apertures 833, hit the baffles 832, andseep/drain to the bottom. Again, the bottom lip is configured to drainthe water out of the entry apertures 833. In some cases, the water maynot necessarily communicate with the entry apertures 833, but maycommunicate with the bottom surface of the splash-proof cap 830. In thiscase, the raised lip around the perimeter of the bottom of thesplash-proof cap 830 and/or the raised lip and each entry aperture 833may block the water so that the water may drop back into the ambientenvironment.

Having described the devices and methods herein, various embodiments caninclude, but are not limited to:

In a first embodiment, a filter comprises a top housing, having at leastone outlet aperture; a bottom housing, having one or more inletapertures; a dustproof membrane; and a waterproof membrane. A secondembodiment can include the filter of the first embodiment, wherein thedustproof membrane is located upstream of the waterproof membrane. Athird embodiment can include the filter of the first or secondembodiments, wherein each of the one or more inlet apertures has adiameter of approximately 6-7 square millimeters (and there typicallymay be 6 such inlet apertures), and wherein the one or more outletapertures has a diameter of 6 millimeters or less (and, typically, theremay be only one such outlet aperture). A fourth embodiment can includethe filter of any of the first to third embodiments, wherein the bottomhousing comprises a raised lip extending around a perimeter of a bottomsurface of the bottom housing. A fifth embodiment can include the filterof any of the first to fourth embodiments, wherein the waterproofmembrane is attached to a top surface of the bottom housing by welding.A sixth embodiment can include the filter of any of the first to fifthembodiments, further comprising a support frame located between thedustproof membrane and the waterproof membrane. A seventh embodiment caninclude the filter of any of the first to sixth embodiments, wherein thesupport frame comprises one or more air flow apertures, and wherein theone or more air flow apertures correspond with the one or more inletapertures in the bottom housing. An eighth embodiment can include thefilter of any of the first to seventh embodiments, wherein the dustproofmembrane is spaced approximately 1-5 (or, alternatively, 1-3, 2-3, 2-5,or 3-5) millimeters from the waterproof membrane. A ninth embodiment caninclude the filter of any of the first to eighth embodiments, furthercomprising a splash-proof cap which comprises a hollow body with a topopen end configured for attachment onto the bottom housing. A tenthembodiment can include the filter of any of the first to ninthembodiments, further comprising: a bottom surface of the hollow bodyhaving one or more entry apertures wherein the bottom surface of thehollow body is curved inward with respect to the hollow body; and one ormore baffles corresponding with the one or more entry apertures in thebottom surface. An eleventh embodiment can include the filter of any ofthe first to tenth embodiments, wherein each of the baffles are alignedwith the corresponding entry aperture, wherein each baffle is generallyparallel to the corresponding entry aperture, wherein each baffle issized to be at least as large as the corresponding entry aperture, andwherein the baffles are located within the hollow body of thesplash-proof cap and spaced approximately 3-4 millimeters from thecorresponding entry aperture. A twelfth embodiment can include thefilter of any of the first to eleventh embodiments, wherein the bottomsurface of the hollow body of the splash-proof cap comprises a raisedlip around the perimeter. A thirteenth embodiment can include the filterof any of the first to twelfth embodiments, wherein the entry aperturesof the splash-proof cap further comprise a raised lip around theperimeter of the entry apertures. A fourteenth embodiment can includethe filter of any of the first to thirteenth embodiments, wherein thesplash-proof cap is removably attached to the bottom housing. Afifteenth embodiment can include the filter of any of the first tofourteenth embodiments, wherein the splash-proof cap further comprisesan elastomeric bumper on an inner surface of the hollow body, configuredto allow press-fit attachment of the splash-proof cap to the bottomhousing. A sixteenth embodiment can include the filter of any of thefirst to fifteenth embodiments, wherein the dustproof membrane comprisespolypropylene nonwoven (PPNW), and wherein the water-proof membranecomprises polytetrafluoroethylene (PTFE). A seventeenth embodiment caninclude the filter of any of the first to seventeenth embodiments,wherein the ratio of the size of the inlet apertures to the size of theoutlet aperture is 6 to 1.

While various embodiments in accordance with the principles disclosedherein have been shown and described above, modifications thereof may bemade by one skilled in the art without departing from the spirit and theteachings of the disclosure. The embodiments described herein arerepresentative only and are not intended to be limiting. Manyvariations, combinations, and modifications are possible and are withinthe scope of the disclosure. Alternative embodiments that result fromcombining, integrating, and/or omitting features of the embodiment(s)are also within the scope of the disclosure. Accordingly, the scope ofprotection is not limited by the description set out above, but isdefined by the claims which follow, that scope including all equivalentsof the subject matter of the claims. Each and every claim isincorporated as further disclosure into the specification, and theclaims are embodiment(s) of the present invention(s). Furthermore, anyadvantages and features described above may relate to specificembodiments, but shall not limit the application of such issued claimsto processes and structures accomplishing any or all of the aboveadvantages or having any or all of the above features.

Additionally, the section headings used herein are provided forconsistency with the suggestions under 37 C.F.R. 1.77 or to otherwiseprovide organizational cues. These headings shall not limit orcharacterize the invention(s) set out in any claims that may issue fromthis disclosure. Specifically and by way of example, although theheadings might refer to a “Field,” the claims should not be limited bythe language chosen under this heading to describe the so-called field.Further, a description of a technology in the “Background” is not to beconstrued as an admission that certain technology is prior art to anyinvention(s) in this disclosure. Neither is the “Summary” to beconsidered as a limiting characterization of the invention(s) set forthin issued claims. Furthermore, any reference in this disclosure to“invention” in the singular should not be used to argue that there isonly a single point of novelty in this disclosure. Multiple inventionsmay be set forth according to the limitations of the multiple claimsissuing from this disclosure, and such claims accordingly define theinvention(s), and their equivalents, that are protected thereby. In allinstances, the scope of the claims shall be considered on their ownmerits in light of this disclosure, but should not be constrained by theheadings set forth herein.

Use of broader terms such as “comprises,” “includes,” and “having”should be understood to provide support for narrower terms such as“consisting of,” “consisting essentially of,” and “comprisedsubstantially of.” Use of the terms “optionally,” “may,” “might,”“possibly,” and the like with respect to any element of an embodimentmeans that the element is not required, or alternatively, the element isrequired, both alternatives being within the scope of the embodiment(s).Also, references to examples are merely provided for illustrativepurposes, and are not intended to be exclusive.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another system,or certain features may be omitted or not implemented.

Also, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as directly coupled or communicating witheach other may be indirectly coupled or communicating through someinterface, device, or intermediate component, whether electrically,mechanically, or otherwise. Other examples of changes, substitutions,and alterations are ascertainable by one skilled in the art and could bemade without departing from the spirit and scope disclosed herein.

What is claimed is:
 1. A filter [210] comprising: a top housing [211],having at least one outlet aperture [219]; a bottom housing [312],having one or more inlet apertures [317]; a dustproof membrane [214];and a waterproof membrane [213]; wherein: the waterproof membrane [213]is located downstream of the dustproof membrane [214].
 2. The filter ofclaim 1 wherein the one or more inlet apertures [317] comprises 6 inletapertures each having a diameter of 6-7 millimeters, wherein there is asingle outlet aperture having a diameter of 6 millimeters or less, andwherein the ratio of the size of the inlet aperture [317] to the size ofthe outlet aperture [219] is approximately 6 to 1 or more.
 3. The filterof claim 1 wherein the waterproof membrane [213] is attached to a topsurface of the bottom housing [212] by welding.
 4. The filter of claim 1further comprising a support frame [215] located between the dustproofmembrane [214] and the waterproof membrane [213], wherein the supportframe comprises one or more air flow apertures [220], and wherein theone or more air flow apertures [220] correspond with the one or moreinlet apertures [317] in the bottom housing [312].
 5. The filter ofclaim 1 wherein the dustproof membrane [214] is spaced approximately 1-5millimeters from the waterproof membrane [213].
 6. The filter of claim 1further comprising a splash-proof cap [130] comprising: a hollow body[131] with a top open end configured for attachment onto the bottomhousing [212] a bottom surface of the hollow body [131] having one ormore entry apertures [133] wherein the bottom surface of the hollow body[131] is curved inward with respect to the hollow body [131]; and one ormore baffles [132] corresponding with the one or more entry apertures[133] in the bottom surface.
 7. The filter of claim 6 wherein eachbaffle [132] is generally parallel to the corresponding entry aperture[133], wherein each baffle [132] is sized to be at least as large as thecorresponding entry aperture [133], and wherein the baffles [132] arelocated within the hollow body [131] of the splash-proof cap [130] andspaced approximately 3-4 millimeters from the corresponding entryaperture [133].
 8. The filter of claim 6 wherein the bottom surface[134] of the hollow body [131] of the splash-proof cap [130] comprises araised lip [136] around the perimeter.
 9. The filter of claim 6 whereineach of the entry apertures [133] of the splash-proof cap [130] furthercomprise a raised lip [436] around the perimeter of each of the entryapertures [133].
 10. The filter of claim 6 wherein the splash-proof cap[130] is removably attached to the bottom housing [112].
 11. The filterof claim 10 wherein the splash-proof cap [130] further comprises anelastomeric bumper [137] on an inner surface of the hollow body [131],configured to allow press-fit attachment of the splash-proof cap [130]to the bottom housing [112].
 12. The filter of claim 1 wherein thedustproof membrane [214] comprises polypropylene nonwoven (PPNW), andwherein the water-proof membrane [213] comprises polytetrafluoroethylene(PTFE).
 13. A filter [210] comprising: a top housing [211], having atleast one outlet aperture [219]; a bottom housing [312], having one ormore inlet apertures [317]; a dustproof membrane [214]; and a waterproofmembrane [213]; wherein: the waterproof membrane [213] is locateddownstream of the dustproof membrane [214], and wherein the waterproofmembrane [213] is spaced approximately 1-5 millimeters away from thedustproof membrane [214]; wherein the ratio of the size of the inletaperture to the size of the outlet aperture is approximately 6 to 1; andwherein the dustproof membrane [214] comprises polypropylene nonwoven(PPNW), and wherein the waterproof membrane [213] comprisespolytetrafluoroethylene (PTFE).
 14. The filter of claim 13 furthercomprising a support frame [215] located between the dustproof membrane[214] and the waterproof membrane [213], wherein the support framecomprises one or more air flow apertures [220], and wherein the one ormore air flow apertures [220] align with the one or more inlet aperturesin the bottom housing [212].
 15. The filter of claim 13 furthercomprising a splash-proof cap [630] wherein the splash-proof cap [630]further comprises: a hollow body [131] with a top open end configuredfor attachment onto the bottom housing [112]; a bottom surface [134] ofthe hollow body [131] having one or more entry apertures [133], whereinthe bottom surface [134] of the hollow body [131] is curved inward withrespect to the hollow body [131]; and one or more baffles [132] alignedwith the corresponding entry apertures [133] in the bottom surface[134], wherein each baffle [132] is generally parallel to thecorresponding entry aperture [133], wherein each baffle [132] is sizedto be at least as large as the corresponding entry aperture [133], andwherein the baffles [132] are located within the hollow body [131] ofthe splash-proof cap [130] and spaced approximately 3-4 millimeters fromthe corresponding entry aperture [133].